This class includes equipment and processes which (a) conceal
or obscure intelligible information by transforming such information
so as to make the information unintelligible to a casual or unauthorized
recipient, or (b) extract intelligible information from such a concealed
representation, including breaking of unknown codes and messages.

(1)Note. Cryptographic processing may include, e.g., scrambling
or masking or their complementary transformations.

(2)Note. All electrical communications equipment which processes
an information signal for purposes of concealment are classified in
this class.

(3)Note. Processing or converting of a signal for purposes of
handling or transmission which may incidentally render a signal unintelligible
are not classified in this class.

(4)Note. Mere blocking of access to the information is not considered
a cryptographic transformation of the signal or information.

(5)Note. A cryptogram or a cryptographic record absent a separate
encrypting or decrypting device is classified elsewhere. See References
to Other Classes, below.

(6)Note. Excluded herein is nominal cryptography in combination
with subject matter of another class. Such subject matter is classified
with the other class. See search notes below.

(7)Note. Excluded herein is subject matter of this class in combination
with the specific environments of a) business data processing or
b) electrical computer or digital processing system support. Such
subject matter is classified elsewhere in the classes providing
for the specific environment. See search notes below.

(8)Note. During the latest reclassification project, a group
of existing subclasses were repositioned as is pending additional
reclassification of this class. However, screening was not done
within this group of subclasses or between this group and the other subclasses
not part of the latest project. This should be taken into consideration when
determining an appropriate field of search.

Electrical Computers and Digital Processing Systems:
Support,
subclasses 150 through 194for cryptographic electrical computer or digital processing
system support, and foreign art collections FOR 123 and FOR 125
for cryptographic user or record authentication.

Interactive Video Distribution Systems,
subclasses 1 through 31for billing, surveying, awarding credit, and access
control or blocking in a video distribution system wherein the video
encryption or scrambling may be nominally claimed.

This subclass is indented under the class definition. Subject matter for evaluating or monitoring the condition
of cryptographic equipment or equipment associated with a cryptographic system.

(1)Note. Associated equipment includes testing or monitoring
of diverse equipment (e.g. communication or display equipment) which
would be classified in either the class providing for the particular
equipment or in a testing class absent association with cryptographic
equipment.

Dynamic Magnetic Information Storage or Retrieval,
subclasses 7and 8+ for delay, and for modification, respectively,
of an electrical signal by recording and subsequent retrieval from
a magnetic record medium.

This subclass is indented under subclass 28. Subject matter which encrypts a digital signal by a sequence
including an initial 64-bit permutation, a 56-bit encryption-key
dependent substitution block computation, and an inversion of the
initial permutation.

(1)Note. The details of this encryption algorithm are published
in the U.S. Government standard: Federal Information Processing
Standard (FIPS) publication No. 46, January 15, 1977, U.S. National Bureau
of Standards.

This subclass is indented under subclass 255. Subject matter which divides the message signal into time
interval segments the order of which are interchanged.

(1)Note. Excluded herein is this subject matter which involves
a magnetic record carrier. Such subject matter is classified with
electric signal modification by magnetic record carrier. See search notes
below.

This subclass is indented under subclass 36. Subject matter wherein time interchanged data segments are
processed either in discrete blocks, or a continuous stream, of
bits or pulses which serially comprise the message stream.

This subclass is indented under subclass 255. Subject matter which encrypts a message signal composed
of a stream of data elements serially and continuously to produce
a stream of the corresponding encrypted data elements.

(1)Note. The encryption may be performed by either modification
of substitution of the data stream elements.

This subclass is indented under subclass 42. Subject matter wherein a predetermined sequence of digital
signals is combined element-for-element with the message signal
data elements to produce an encrypted or decrypted signal.

This subclass is indented under the class definition. Subject matter which includes a detail of the configuration
or arrangement of the cryptographic equipment of communications
equipment connected thereto.

(1)Note. Such equipment may include an enclosure, keyboard display,
etc.

This subclass is indented under the class definition. Subject matter which changes the visible appearance of an
object so as to encrypt visible markings, or to decode the appearance
of the object into intelligible visible markings.

This subclass is indented under the class definition. Subject matter for encrypting a message signal which is
composed of distinct intelligible characters which are visibly positioned
on relatively movable surfaces to enable transposing or substituting
such characters.

(1)Note. The term "character" is intended to mean at least a
distinct intelligible element, but also includes phrases, numbers,
etc., as the intelligence bearing or the encrypted message

Interactive Video Distribution Systems,
subclasses 1 through 31for billing, surveying, awarding credit, and access
control or blocking in a video distribution system wherein the video encryption
or scrambling may be nominally claimed.

for video signal modification which has usage or
charge determination ncluding authentication, subclasses 247-250
for cellular phone cryptographic authentication, and subclass 258
for a communication system which is position dependent or has authentication.

Data Processing: Financial, Business Practice, Management, or
Cost/Price Determination,
subclasses 52 through 54for usage protection of distributed data files
including usage or charge determination, subclasses 77
through 79 for a cryptographic electric commerce system including
billing and subclasses 1.1 and 2 through 45 for automated
electrical financial or business practice or management arrangement.

for video signal modification which is record or
coin controlled and includes authentication, subclasses 247-250
for cellular phone cryptographic authentication, and subclass 258
for a communication system which is position dependent or has authentication.

for video signal modification which is record or
coin controlled and includes authentication, subclass 232 for video signal
modification which has usage or charge determination including authentication,
subclass 258 for a communication system which is position dependent
or has authentication, and subclasses 270 - 274 for cryptography
in a wireless communication system.

This subclass is indented under 255. Subject matter wherein protection of the transmission or
reception of information occurs in a system having plural nodes
joined by switched physical links (usually two-way voice).

(1)Note. Excluded herein is symmetric key cryptography which
includes a modem. This is classified elsewhere.

for video signal modification which is record or
coin controlled and includes authentication, subclass 232
for video signal modification which has usage or charge determination
including authentication, and subclasses 247- 250
for cellular phone cryptographic authentication.

Communications: Directive Radio Wave
Systems and Devices (e.g., Radar, Radio
Navigation),
subclasses 357.2 through 357.78for directive radio wave systems including a satellite
with position indicating.

This subclass is indented under 255. Subject matter including cryptographic structure or methods
which protect the transmission or reception of information over
a nonphysical link by electromagnetic waves.

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